RE: stringification of objects, subroutine refs
[EMAIL PROTECTED]:
# I was wondering how perl6 would stringify (as in Data::Dumper):
As Dan said, that's serialization. I don't know if Perl will support
that built-in. But if it does...
# 1) objects with 'my' and 'our' variables
Those would have to be dumped from the pads or stashes. I don't think
there's any way around that.
# 2) $.property
Using their accessors?
# 2) subroutines (and coderefs)
See my comment below.
# 3) properties (both is/has)
'is' properties are part of the code, so I don't think they need
serialization. 'has' (or whatever it'll be called) properties can be
applied easily--remember, a 'has' returns its left operand.
# Right now, the fact that subroutines come out as 'sub {
# DUMMY }' is a minor pain to work around, having all of
# these as holes would be too much IMO.
That's fixed in 5.8--it uses B::Deparse to make a rough version of the
sub. Just hope it isn't a closure.
--Brent Dax [EMAIL PROTECTED]
@roles=map {Parrot $_} qw(embedding regexen Configure)
blink: Text blinks (alternates between visible and invisible).
Conforming user agents are not required to support this value.
--The W3C CSS-2 Specification
Attribute vs. Property
I just want to verify that I properly understand the use of these two terms in Perl 6. * An attribute is a data member of a class. * A property is a piece of metadata on a...uh...thing -- e.g., on an attribute, on a class, or on a method. Do I have it right? For some reason, I've always referred to class data members as properties, and thought of metadata on such things as attributes -- the reverse of the above. This despite the use of attribute in the above usage in Damian's book. So do I just need to turn myself around (at least when talking about Perl), or is there a chance that the language designers would decide that the way I use the terms is ever-so-much-better? ;-) Regards, David -- David Wheeler AIM: dwTheory [EMAIL PROTECTED] ICQ: 15726394 http://david.wheeler.net/ Yahoo!: dew7e Jabber: [EMAIL PROTECTED]
Selective exporting of properties/methods
While thinking Eiffel-ish thoughts the other day, I began to wonder if
Perl6's classes could go beyond the simple private/public/protected
scheme by optionally allowing for a property or method to only be
accessed by a certain set of classes. For instance(as I understand
Perl6 syntax):
class Foo {
method hello is public {
return hello;
}
method world is public_to(Bar) {
# is only public to objects of class Bar
return world;
}
}
class Bar {
method say_hello {
# this works fine
print Foo.new.hello, \n;
}
method say_world {
# as does this
print Foo.new.world, \n;
}
}
class Baz {
method say_world {
# generates a run-time exception for trying to call a private method.
print Foo.new.world, \n;
}
}
Re: Accessor methods ?
On Fri, May 10, 2002 at 11:27:53PM -0400, Chris Dutton wrote:
On Friday, May 10, 2002, at 09:54 PM, Damian Conway wrote:
That's getting a little ugly, so maybe we'd lift the syntax from
Eiffel instead:
method set_baz($newbaz is like($.baz)) { $.baz = $newbaz }
This is exactly what went through my mind about a half second after I
posted the message.
$newbaz is like($.baz), I would think, would have to raise a run-time
exception if $newbaz isn't like $.baz.
I've always found the word like to be very wishy-washy in a computer
langauge. In what way is newbaz like baz? And just how alike are they?
There must be a better way to describe this.
--
Paul Johnson - [EMAIL PROTECTED]
http://www.pjcj.net
Re: Attribute vs. Property
David Wheeler wrote: I just want to verify that I properly understand the use of these two terms in Perl 6. and in the wider OO community, BTW. * An attribute is a data member of a class. Yes. * A property is a piece of metadata on a...uh...thing -- e.g., on an attribute, on a class, or on a method. or on a subroutine, closure, or value. Do I have it right? Yes. So do I just need to turn myself around (at least when talking about Perl), or is there a chance that the language designers would decide that the way I use the terms is ever-so-much-better? ;-) Well, I suppose there's always a *chance* that we'd both completely reverse our careful thinking on this issue and ignore the common usage of attribute in the OO literature. But I do think it would be easier all round if you just went with our chosen terminology for Perl 6. ;-) Damian
Re: Attribute vs. Property
On 5/11/02 2:48 PM, Damian Conway [EMAIL PROTECTED] claimed: Well, I suppose there's always a *chance* that we'd both completely reverse our careful thinking on this issue and ignore the common usage of attribute in the OO literature. But I do think it would be easier all round if you just went with our chosen terminology for Perl 6. ;-) Damn. I was afraid you were going to say that! :-) Thanks for the reply. Regards, David -- David Wheeler AIM: dwTheory [EMAIL PROTECTED] ICQ: 15726394 http://david.wheeler.net/ Yahoo!: dew7e Jabber: [EMAIL PROTECTED]
Re: Accessor methods ?
On 5/11/02 2:43 PM, Damian Conway [EMAIL PROTECTED] claimed:
method set_baz($newbaz is compatible($.baz)) { $.baz = $newbaz }
method set_baz($newbaz is typeof($.baz)) { $.baz = $newbaz }
I like the latter best -- and it beats the hell out of instanceof ;-)
Regards,
David
--
David Wheeler AIM: dwTheory
[EMAIL PROTECTED] ICQ: 15726394
http://david.wheeler.net/ Yahoo!: dew7e
Jabber: [EMAIL PROTECTED]
Re: Accessor methods ?
David Wheeler [EMAIL PROTECTED] writes:
On 5/11/02 2:43 PM, Damian Conway [EMAIL PROTECTED] claimed:
method set_baz($newbaz is compatible($.baz)) { $.baz = $newbaz }
method set_baz($newbaz is typeof($.baz)) { $.baz = $newbaz }
I like the latter best -- and it beats the hell out of instanceof ;-)
talking about instanceof, here are the various syntaxes:
* testing class membership
x isax Perl x
x is_a? kind_of? x Ruby x
x dynamic_cast x C++ x
x instanceof x Java x
x isinstance x Python x
x in x Ada x
x is x C# x
x is_a x PHP x
x entry_type x Pliant x
x ISTYPE x Modula-3 x
x object## classname## x Beta x
x var ?= val (20)x Eiffel x
* get the class corresponding to an object/instance
x type x Ruby x
x __class__ x Python x
x getClass x Java x
x typeidx C++x
if you know some more, tell me :)
http://merd.net/pixel/language-study/syntax-across-languages.html
